Transmission protocols within communications systems may include the use of single-ended signals, differential signals, or combinations of single-ended and differential signals. For example, single-ended signals and differential signals are suitable for use in portable communications systems that employ low speed data transmission. However, in communications systems that employ high speed data transmission, it is desirable to use differential signals because of their noise immunity properties. These types of systems include mobile electronic devices such as, for example, smartphones, tablets, computers, and systems that include Universal Serial Bus (USB) applications. In addition to noise immunity, it is desirable to include protection from large transient voltage and current spikes, which can damage these systems. Typically, noise filters, also known as Common Mode Filters (CMF) and Electro-Static Discharge (ESD) protection circuits are mounted to a Printed Circuit Board (PCB) along with other circuitry of the communications system to reduce common mode noise on differential signal lines and to suppress large transient electrical spikes, respectively. This configuration of elements occupies a large area on a PCB, which is disadvantageous in mobile electronic devices. The ESD protection circuits are fabricated from low resistivity substrates to accommodate high currents encountered during ESD events. It is undesirable to manufacture filter elements such as inductor coils on a low resistivity substrate because of the presence of eddy currents which degrade filter performance.
Accordingly, it would be advantageous to have a structure and method for manufacturing a semiconductor component that provides protection from large electrical transients and provides noise filtering. It would be of further advantage for the structure and method to be cost efficient to implement.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference characters in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current flow through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain n-channel or p-channel devices, or certain n-type or p-type doped regions, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with embodiments of the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. The use of the words approximately, about, or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to about ten per cent (10%) (and up to twenty percent (20%) for semiconductor doping concentrations) are regarded as reasonable variances from the ideal goal of exactly as described.